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Message-ID: <20240703104640.20878-1-fw@strlen.de>
Date: Wed, 3 Jul 2024 12:46:34 +0200
From: Florian Westphal <fw@...len.de>
To: dev@...nvswitch.org
Cc: pshelar@....org,
netdev@...r.kernel.org,
Florian Westphal <fw@...len.de>
Subject: [PATCH net-next] openvswitch: prepare for stolen verdict coming from conntrack and nat engine
At this time, conntrack either returns NF_ACCEPT or NF_DROP.
To improve debuging it would be nice to be able to replace NF_DROP
verdict with NF_DROP_REASON() helper,
This helper releases the skb instantly (so drop_monitor can pinpoint
precise location) and returns NF_STOLEN.
Prepare call sites to deal with this before introducing such changes
in conntrack and nat core.
Signed-off-by: Florian Westphal <fw@...len.de>
---
net/openvswitch/conntrack.c | 47 +++++++++++++++++++++++++++++--------
1 file changed, 37 insertions(+), 10 deletions(-)
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 3b980bf2770b..8eb1d644b741 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -679,6 +679,8 @@ static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
action |= BIT(NF_NAT_MANIP_DST);
err = nf_ct_nat(skb, ct, ctinfo, &action, &info->range, info->commit);
+ if (err != NF_ACCEPT)
+ return err;
if (action & BIT(NF_NAT_MANIP_SRC))
ovs_nat_update_key(key, skb, NF_NAT_MANIP_SRC);
@@ -697,6 +699,22 @@ static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
}
#endif
+static int verdict_to_errno(unsigned int verdict)
+{
+ switch (verdict & NF_VERDICT_MASK) {
+ case NF_ACCEPT:
+ return 0;
+ case NF_DROP:
+ return -EINVAL;
+ case NF_STOLEN:
+ return -EINPROGRESS;
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
/* Pass 'skb' through conntrack in 'net', using zone configured in 'info', if
* not done already. Update key with new CT state after passing the packet
* through conntrack.
@@ -735,7 +753,7 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
err = nf_conntrack_in(skb, &state);
if (err != NF_ACCEPT)
- return -ENOENT;
+ return verdict_to_errno(err);
/* Clear CT state NAT flags to mark that we have not yet done
* NAT after the nf_conntrack_in() call. We can actually clear
@@ -762,9 +780,12 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
* the key->ct_state.
*/
if (info->nat && !(key->ct_state & OVS_CS_F_NAT_MASK) &&
- (nf_ct_is_confirmed(ct) || info->commit) &&
- ovs_ct_nat(net, key, info, skb, ct, ctinfo) != NF_ACCEPT) {
- return -EINVAL;
+ (nf_ct_is_confirmed(ct) || info->commit)) {
+ int err = ovs_ct_nat(net, key, info, skb, ct, ctinfo);
+
+ err = verdict_to_errno(err);
+ if (err)
+ return err;
}
/* Userspace may decide to perform a ct lookup without a helper
@@ -795,9 +816,12 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
* - When committing an unconfirmed connection.
*/
if ((nf_ct_is_confirmed(ct) ? !cached || add_helper :
- info->commit) &&
- nf_ct_helper(skb, ct, ctinfo, info->family) != NF_ACCEPT) {
- return -EINVAL;
+ info->commit)) {
+ int err = nf_ct_helper(skb, ct, ctinfo, info->family);
+
+ err = verdict_to_errno(err);
+ if (err)
+ return err;
}
if (nf_ct_protonum(ct) == IPPROTO_TCP &&
@@ -1001,10 +1025,9 @@ static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
/* This will take care of sending queued events even if the connection
* is already confirmed.
*/
- if (nf_conntrack_confirm(skb) != NF_ACCEPT)
- return -EINVAL;
+ err = nf_conntrack_confirm(skb);
- return 0;
+ return verdict_to_errno(err);
}
/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
@@ -1039,6 +1062,10 @@ int ovs_ct_execute(struct net *net, struct sk_buff *skb,
else
err = ovs_ct_lookup(net, key, info, skb);
+ /* conntrack core returned NF_STOLEN */
+ if (err == -EINPROGRESS)
+ return err;
+
skb_push_rcsum(skb, nh_ofs);
if (err)
ovs_kfree_skb_reason(skb, OVS_DROP_CONNTRACK);
--
2.44.2
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